The present invention relates to a device for holding a cable suspended from a support, and more particularly a cable of the type having an aerial support wire connected therealong for supporting same, such as the steel messenger coaxial cable used in the cable TV industry.
Applicant has already described in his Canadian Patent No. 982,787 of Feb. 3, 1976 a wedge clamp for securing a coaxial television cable to a support. This wedge clamp comprises a conical body member formed with a longitudinal outer groove having a depth smaller than the diameter of the cable for receiving the cable such as to leave a cable portion protruding therefrom, and a conical wedge sleeve for mounting over the body member and formed with a longitudinal slot for passing the cable therethrough. The conical body member is also provided at its smaller end with means for connecting it to a support. Thus, in use, the wedge sleeve is mounted over the body member with the slot in axial alignment with the groove, the cable is inserted in the groove through the slot and the sleeve is rotated over the body member to clamp the cable therebetween.
Since nowdays coaxial TV cables are generally no longer used alone but rather in combination with a steel messenger wire which is connected therealong by means of the PVC or rubber coating covering both the cable and messenger wire, for the purpose of supporting the cable suspended above ground between two remote connection points, Applicant's cable clamp described above cannot be used successfully to secure this type of cable to a support, such as a pole or a housing. As the primary purpose of the messenger wire is to support the cable suspended above ground and to thereby prevent axial tensions from being exerted along the cable, it is that wire which must be secured to the support, instead of the cable itself. Thus, when using Applicant's wedge clamp, sufficient clamping pressure cannot be exerted on the messenger wire owing to the difference in size between the messenger wire and the cable, the messenger wire having a much smaller diameter than the cable. As a result, the steel wire cannot be positively held and therefore has a tendency of slipping within its plastic jacket.
Other devices are also known for securing a guy wire to a support and have been used for holding a messenger coaxial cable suspended therefrom. One such device is the so-called guy thimble which consists of an elongated piece of metal bent to define an open loop and formed with a longitudinal outer groove for seatingly receiving over the loop a dead-end portion of the messenger wire which has been separated from the cable, with the dead-end of the wire being wound around the messenger wire itself adjacent the ends of the loop for positive securement. Due to the particular configuration of this device, the dead-end portion of the messenger wire often slips away during installation, thus rendering the latter difficult and time consuming. Different sizes of guy thimbles are also required for different sizes of messenger wires. Moreover, since the loop is generally small in diameter and is mounted over an eye bolt or hook secured to the support, the dead-end of the messenger wire is held close to the point of attachment to the support, resulting in fatigue or stress being induced in the nearby cable portion upon swinging movement of the attachment due to weather conditions. As the cable and messenger wire which remain connected together adjacent the winding of the wire dead-end portion over the loop are not positively retained together by any means other than their own plastic coating, they often undergo further separation when separating forces are exerted thereon.
Another known device consists of a preformed grip wire bent to define a closed loop and having elongated, twisted end portions adapted to be wound around the dead-end portion of the messenger wire. This grip wire basically suffers from the same disadvantages noted above in respect to the guy thimble, in addition to not being reusable.